magnetic force:attraction for iron,associated with electric currents as well as magnets; characterized by fields of force: A force that is between two electric charged things. magnetic field:a region of space near a magnet, electric current, or moving charged particle in which a magnetic force acts on any other magnet, electric current, or moving charged particle. Space near a region and magnet,electric current,or charged particle. electromagnetism:the phenomena associated with electric and magnetic fields and theirinteractionswith each other and with electric charges and currents. electric generator: an electric generator is a device that converts mechanical energy to electrical energy. The reverse conversion of electrical energy into. A machine that converts mechanical energy to electric energy.
solenoid: an electric conductor wound as a helix with small pitch, or as two or more coaxial helices, so that current through the conductor establishes a magnetic field within the conductor. Electric machine and it establishes a magnetic field in the conductor. electric motor:a comparatively small and powerful engine, esp. an internal-combustion engine in an automobile, motorboat, or the like. A self powered vehicle.
Links:
This site gives an explanation of prinicples and experiments.
Electromagnets attracts paper clips when current is applied creating a magnetic field. The electromagnet loses them when current and magnetic field are removed.
A simple electromagnet consisting of a coil of insulated wire wrapped around an iron core. When an electric current is passed through the wire, the iron becomes a magnet.
Current (I) through a wire produces a magnetic field (B). The field is oriented according to the right-hand rule.
Magnetic field produced by a solenoid (coil of wire). This drawing shows a cross section through the center of the coil. The crosses are wires in which current is moving into the page; the dots are wires in which current is moving up out of the page.
Magnetic field (green) of a typical electromagnet, with the iron core C forming a closed loop with two air gaps G in it. Most of the magnetic field B is concentrated in the core. However some of the field lines BL, called the "leakage flux", do not follow the full core circuit and so do not contribute to the force exerted by the electromagnet. In the gaps G the field lines spread out beyond the boundaries of the core in "fringing fields" BF. This increases the "resistance" (reluctance) of the magnetic circuit, decreasing the total magnetic flux in the core. Both the leakage flux and the fringing fields get larger as the gaps are increased, reducing the force exerted by the magnet. Line L shows the average length of the magnetic circuit, used in equation (1) below. It is the sum of the length Lcore in the iron core and the length Lgap in the air gaps
Questions:
1.Can electromagets be used to repel as well as attract?
2.How far away from the electromagnet can you hold attracted material?
3.Can you use a battery to power an electromagnet?
4.Can the holding force of an electromagnet be adjusted?
5.Can you attract any metal with an electromagnet?
6.Does the thickness of material attracted effect holding forces?
7.How are holding forces calculated?
8.Is an electromagnet that is rated for 24 vdc stronger than a unit that is rated for 12 vdc?
9.Does ambient temperature affect the performance of electromagnets?
0807.12.2 The basic priniciples of an electromagnet
Table of Contents
Vocabulary:
magnetic force:attraction for iron,associated with electric currents as well as magnets; characterized by fields of force: A force that is between two electric charged things.magnetic field: a region of space near a magnet, electric current, or moving charged particle in which a magnetic force acts on any other magnet, electric current, or moving charged particle. Space near a region and magnet,electric current,or charged particle.
electromagnetism: the phenomena associated with electric and magnetic fields and their interactions with each other and with electric charges and currents.
electric generator: an electric generator is a device that converts mechanical energy to electrical energy. The reverse conversion of electrical energy into. A machine that converts mechanical energy to electric energy.
solenoid: an electric conductor wound as a helix with small pitch, or as two or more coaxial helices, so that current through the conductor establishes a magnetic field within the conductor. Electric machine and it establishes a magnetic field in the conductor.
electric motor: a comparatively small and powerful engine, esp. an internal-combustion engine in an automobile, motorboat, or the like. A self powered vehicle.
Links:
This site gives an explanation of prinicples and experiments.
http://www.wisegeek.com/what-is-an-electromagnet.htm
This site tells what an electromagnet is.
http://www.pureenergysystems.com/os/EdGrayMotor/PM_PEM_MG/principles/index.html
This website tell about an electromagnet motor.
http://en.wikipedia.org/wiki/Electromagnet
This website tells all about electromagnets.
http://www.howstuffworks.com/electromagnet.htm
This website tells about how Electromagnets work.
Pictures:
Electromagnets attracts paper clips when current is applied creating a magnetic field. The electromagnet loses them when current and magnetic field are removed.
A simple electromagnet consisting of a coil of insulated wire wrapped around an iron core. When an electric current is passed through the wire, the iron becomes a magnet.
Current (I) through a wire produces a magnetic field (B). The field is oriented according to the right-hand rule.
Magnetic field produced by a solenoid (coil of wire). This drawing shows a cross section through the center of the coil. The crosses are wires in which current is moving into the page; the dots are wires in which current is moving up out of the page.
Magnetic field (green) of a typical electromagnet, with the iron core C forming a closed loop with two air gaps G in it. Most of the magnetic field B is concentrated in the core. However some of the field lines BL, called the "leakage flux", do not follow the full core circuit and so do not contribute to the force exerted by the electromagnet. In the gaps G the field lines spread out beyond the boundaries of the core in "fringing fields" BF. This increases the "resistance" (reluctance) of the magnetic circuit, decreasing the total magnetic flux in the core. Both the leakage flux and the fringing fields get larger as the gaps are increased, reducing the force exerted by the magnet. Line L shows the average length of the magnetic circuit, used in equation (1) below. It is the sum of the length Lcore in the iron core and the length Lgap in the air gaps
Questions:
1.Can electromagets be used to repel as well as attract?2.How far away from the electromagnet can you hold attracted material?
3.Can you use a battery to power an electromagnet?
4.Can the holding force of an electromagnet be adjusted?
5.Can you attract any metal with an electromagnet?
6.Does the thickness of material attracted effect holding forces?
7.How are holding forces calculated?
8.Is an electromagnet that is rated for 24 vdc stronger than a unit that is rated for 12 vdc?
9.Does ambient temperature affect the performance of electromagnets?
References:
http://www.apwcompany.com
http://www.wikipedia.org/
http://www.sciencecentral.com
http://www.pureenergysystems.com
http://www.howstuffworks.com/
Tcap Coach Book
8th grade Science book